1. Field of the Invention
The present invention relates to a drive unit for a carrier for patient handling devices and medical equipment. The drive unit has a processor programmed to control operation of the unit. Included features are a fail safe mode for unintended loss of power, a runtime control to prevent overheating of an air compressor and a battery charge sensor such that the unit is shut down during periods of inactivity.
2. Brief Description of the Prior Art
Health care facilities utilize a wide variety of patient handling and equipment moving carriers. Examples of such carriers include beds, gurneys, stretchers, wheelchairs, bed chairs and other types of devices that are designed to help support a patient. Other carriers are used to transport medical equipment such as scanners and the like. In some prior art carriers such as described in U.S. Pat. No. 7,191,854 to Lenkman, the carrier includes a chassis having casters at each corner and a drive unit with a wheel that is pivotable with an air spring in and out of contact with a surface over which the carrier is propelled. A processor controls the active status of an independent motor control system for rotating the wheel and the operation of an air compressor for inflating the air spring. Areas for improvement include, if there is a leak in the pneumatic system the compressor may overheat and if there is an unintended interruption in power, the drive wheel may lose traction with the support surface. Additionally, during period of inactivity, such as if the unit is accidentally left on, battery charge may be wasted.